To make filthy or dirty; pollute: defile a river with sewage. To debase the pureness or excellence of; corrupt: a country landscape that was defiled by urban sprawl. To profane or sully (a reputation, for example). To make unclean or unfit for ceremonial use; desecrate: defile a temple. To violate the chastity of. To march in single file or in files or columns. A narrow gorge or pass that restricts lateral movement, as of troops. A march in a line.